This invention relates to devices for automatically venting pressurized air from a compartment in aircraft in the event that the pressure in an adjacent compartment is accidentally lost in flight.
In a recent highly publicized aircraft accident, the pressure in a lower cargo compartment of the craft was accidentally released by loss of a cargo hatch in flight, following which the resultant differential pressure between a still pressurized upper passenger compartment and the depressurized lower compartment caused a separating deck to be deformed downwardly in a manner damaging control cables beneath the deck and eventuating in complete loss of control and an ultimate disastrous crash of the craft. Since that time, various expedients have been proposed for attempting to prevent repetition of the accident, by providing for the rapid venting of any such still pressurized compartment after accidental depressurization of another compartment, to thus avoid subjection of any intermediate deck or wall of the craft to possibly damaging differential pressures.
One such prior proposal of which I am aware utilizes an apertured return grille in the passenger compartment as a venting element, which under normal operating conditions passes a relatively light flow of return air from the passenger compartment into a hollow side wall of the compartment for discharge therefrom, and which under the discussed depressurization conditions swings automatically to a more open position in which a vastly increased volume of air can flow past the retracted grille for quickly discharging the pressurized air from the compartment. The grille in that arrangement is mounted pivotally at its upper edge to enable the lower edge of the grille to swing into the hollow wall. A pair of actuating plates are connected pivotally to the grille and to a support structure at spaced locations, and are connected pivotally to one another at an intermediate location, with the compartment pressure being communicated to these plates in a relation pressure actuating them to swing the grille to its retracted or open position in response to depressurization beyond the plates. In the normal position of the grill, the two plates are in slightly overcenter relative positions, for effectively locking the grille against unwanted opening movement except in response to development of a differential pressure across the plates in a depressurization situation.